package com.chang.multithread.deadlock;

import lombok.extern.slf4j.Slf4j;

import java.util.Random;

//按照顺序获取锁  不会出现死锁状态  但有的线程会出现饥饿现象，一直获得不到锁
public class DeadLockOrder {
    public static void main(String[] args) {
      Chopstick c1 = new Chopstick("1");
      Chopstick c2 = new Chopstick("2");
      Chopstick c3 = new Chopstick("3");
      Chopstick c4 = new Chopstick("4");
      Chopstick c5 = new Chopstick("5");
        new Philosopher("苏格拉底", c1, c2).start();
        new Philosopher("柏拉图", c2, c3).start();
        new Philosopher("亚里士多德", c3, c4).start();
        new Philosopher("赫拉克利特", c4, c5).start();
        new Philosopher("阿基米德", c1, c5).start();
    }
}

@Slf4j
class Philosopher extends Thread {
    Chopstick left;
    Chopstick right;

    public Philosopher(String name, Chopstick left, Chopstick right) {
        super(name);
        this.left = left;
        this.right = right;
    }

    @Override
    public void run() {
        while (true) {
            //　尝试获得左手筷子
            synchronized (left) {
                // 尝试获得右手筷子
                synchronized (right) {
                    eat();
                }
            }
        }
    }

    Random random = new Random();
    private void eat() {
        log.debug("eating...");
        try {
            Thread.sleep(200);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

class Chopstick {
    String name;

    public Chopstick(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "筷子{" + name + '}';
    }
}